The present invention relates to Doppler echocardiography, and more particularly, to detection and measurement mitral valve inflow patterns in Doppler echocardiography.
Doppler echocardiography is widely used in clinical practices to assess heart valve functionality as the blood velocity is recorded. The conventional workflow of Doppler analysis requires manual tracing of the envelopes of acquired Doppler spectra. Once the envelopes of the acquired Doppler spectra are traced, clinically relevant measurements are computed based on the traced envelopes. The manual tracing is a main bottleneck of the workflow. Accordingly, a method for automatically detecting envelopes in the Doppler spectra is desirable.
Mitral valve inflow (MI) patterns and measurements have been studied extensively as indices of left ventricular diastolic function. FIGS. 1A and 1B illustrate exemplary MI Doppler spectra with expert annotated envelopes overlaid thereon. The MI pattern, which occurs in the ventricular diastole phase, typically includes an “early” wave (E-wave) and an “atrial” wave (A-wave). For normal hearts, the E-waves and A-waves do not overlap each other and the E-wave is higher than the A-wave. FIG. 1A illustrates exemplary MI Doppler echocardiography images 110, 120, 130, and 140 in which the E-waves 112, 122, 132, and 142 do not overlap with the A-waves 114, 124, 134, and 144. For diseased hearts, the following can occur: the E-waves and the A-waves can overlap depending on the heart diseases; the E-wave can be lower than or at the same height as the A-wave; or only the E-wave may be present with no A-wave. FIG. 1B illustrates exemplary MI Doppler echocardiography images 150, 160, 170, and 180 in which the E-waves 152, 162, 172, and 182, overlap with the A-waves 154, 164, 174, and 184. The above factors contribute significant variation in the envelope shape of MI Doppler spectra. In terms of image appearance, the variation is too large to apply conventional techniques, such as signal aliasing, difference in imaging setting, etc. for detecting the envelopes.
Some conventional approaches utilize image processing/filtering techniques, such as low-pass filtering, thresholding, and edge detection to attempt to automatically trace Doppler spectra envelopes. However, such techniques do not guarantee robustness in the presence of severe image artifacts.